Various types of printing apparatus utilize replaceable printing sleeves, such sleeves typically being slid axially over a respective cylinder with the aid of compressed air exiting from holes in the outer surface of the cylinder. For example, replaceable printing sleeves used as printing blankets in offset lithographic printing are known, as are printing sleeves in flexographic printing. In electrostatographic printing apparatus imaging cylinders with photoconductive film sleeves may be replaceable as described above.
Offset lithographic printing apparatus include a plate cylinder and a blanket cylinder. The plate cylinder carries a printing plate having a surface on which an inked image is formed. The blanket cylinder carries a printing blanket. The plate on the plate cylinder transfers the inked image to the blanket on the blanket cylinder at a nip between the plate cylinder and the blanket cylinder. The blanket on the blanket cylinder subsequently transfers the inked image to the receiver material, such as a sheet or web of paper. In electrostatographic printing an electrostatic latent image is formed on a primary image-forming member such as a photoconductive surface and is developed with a thermoplastic toner powder to form a toner image. The toner image is thereafter transferred to a receiver member, e.g., a sheet of paper or plastic, and the toner image is subsequently fused or fixed to the receiver member in a fusing station using heat and/or pressure.
Offset lithographic printing blankets and electrostatographic photoconductive imaging members may both be formed as a tube which is mounted on a respective cylinder by sliding the tube axially over the cylinder. Such printing members will henceforth be generically referred as printing sleeves. Typically such printing sleeves include a metal cylindrical sleeve, for example nickel, aluminum, or the like, with the active printing element applied to the outer surface. The printing sleeve is receivable over the respective cylinder with an interference fit. The cylinder is equipped with air flow passages and openings to direct a pressurized flow of air over the outer surface of the cylinder. When the printing sleeve is located over the air flow openings in the cylinder, the pressurized flow of air expands the printing sleeve diametrically. The printing sleeve can be move axially onto or off of, the cylinder when in its expanded condition. When the pressure is relieved, the sleeve contracts diametrically against the cylinder and thus establishes an interference fit with the cylinder.
An unpleasant result of using pressurized air to install printing sleeves over cylinders as described above is a rather loud, high pitched noise that results from the high pressure, high velocity air flow between the printing sleeve and cylinder. Such noise begins as soon as the printing sleeve begins to expand as the lead edge passes over the first air flow openings and persists until the printing sleeve is completely slid over the cylinder and the air pressure is relieved.
U.S. Pat. No. 5,215,013 to Vrotacoe, et al. discloses a tubular printing blanket with a damping ring on the inside of the tube at one end to dampen vibrations of the tube and reduce the resultant noise. The device of the Vrotacoe patent has the disadvantages that a damping ring is required on every sleeve, thus increasing the cost, and only adequately reduces noise when the sleeve is placed fully over the cylinder, not during axial sliding. Also, the sleeve with damping ring at one end can only be installed with the opposite end as lead edge. U.S. Pat. No. 6,347,586 to Boucher, et al. discloses a cylinder provided with a sound-damping surface to an outer surface of the cylinder at the free end. A disadvantage of the approach of the Boucher patent is that it requites an extension of the cylinder thereby requiring more space.